BREAST CYTOPATHOLOGY

Special Types of Breast Carcinomas 123
Figure 4.43. Apocrine carcinoma. A loosely cohesive cluster of
large, pleomorphic malignant cells. Note the occasional binucleation
and abundant granular cytoplasm in the tumor on the left. The corresponding
histologic section is shown on the right. (Smear, Papanicolaou;
histologic section, hematoxylin and eosin.)
• Cytologic evidence of malignancy is often easy to appreciate
(nuclear overlap, pleomorphism, high nucleus to cytoplasm
ratios, occasional mitoses).
• Pleomorphic large nuclei are often eccentrically located
within the dense granular or clear eosinophilic cytoplasm.
Cells are often binucleated with discrete and well-delineated
cytoplasmic borders.
• The nucleoli are prominent, and multinucleation is
common.
• Background consists of fragmented cytoplasm with naked
malignant nuclei and granular debris.
• Eccentric nuclear placement gives the cells a “cometlike”
morphology.
• Occasionally necrosis and/or histiocytes are seen.
• It represents one of the gray zone cytopathologic diagnoses
on FNA.
• In difficult cases, immunostaining with Ki-67 (higher
expression) and p53 can be helpful.